July 25, 2011 -- When we are feeling sad, many of us reach for comfort foods such as chocolate, ice cream, or chips. Now new research helps show how these foods boost our moods.

Researchers led by Lukas Van Oudenhove, MD, PhD, at the University of Leuven in Belgium, used functional MRI scans to chart the areas of the brain that lit up when 12 healthy non-obese individuals experienced sadness and then received an infusion of fatty acid or saline delivered via a feeding tube. Many comfort foods have a substantial amount of fatty acids.

Participants listened to sad or neutral music while viewing corresponding images of sad or neutral faces. They were asked to rate fullness, hunger, and mood before the MRI scan and three times during the brain scan.

The participants did not know which infusion they received. But those who got the fatty acid blast reported feeling about half as sad as those who received the saline infusion.

The study appears in the Journal of Clinical Investigation.

"These findings increase our understanding of the interplays among emotions, hunger, food intake and meal-induced sensations in general which may have important implications for a wide range of disorders including obesity, eating disorders, and depression," the researchers conclude.

Your Gut Talks to Your Brain

Giovanni Cizza, MD, of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, MD, co-authored an accompanying editorial. "We did not know if you put fat in the stomach without pleasant stimulus, it could modulate our emotions," he says. "There must be a way in which the gut talks to the brain."

The research may lead to new drug developments if researchers can home in on an appropriate target in the gut.

Louis Aronne, MD, founder and director of the Comprehensive Weight Control Program at New York-Presbyterian Hospital/Weill Cornell Medical Center, says the findings are a major step forward to our understanding of some of the physical underpinnings of the relationship between food and mood.

"The areas of the brain that get activated or suppressed as a result of emotion and mood were impacted by fatty acid emulsion," he says. "These fats reduced some of the emotion or neural changes, and this is a phenomenon that many patients have described."

"Many things in obesity have been said to be psychological and this adds to the body of evidence that something physical is going on," he says.

The new study looked at non-obese individuals, and the effects may be even more pronounced in obese or overweight people, he says.

"People who are obese may have to eat more to get the same stimulation as normal-weight individuals," he says.

Mood Foods

"Emotional eating is a coping mechanism to deal with intense feelings, stress, or depressed moods increasing one's chance of obesity," says Treena Wynes, a wellness consultant in Saskatoon, Canada, in an email. "Our urge to eat is strongly driven by our moods and emotions."

"Fatty-acids provide the positive benefits for enhancing moods and brain function which improve our thinking, feelings, and behavior [and] are becoming recognized for their mood-stabilizing and antidepressant effects as well as satiety," she says.